The present invention relates to a method for forming a pouch in a tubular article, particularly for forming the heel or toe of hosiery items, with circular hosiery knitting machines having at least two feeds or drops.
As is known, in the conventional production of hosiery items with circular machines the heel and toe of the hosiery item are formed by using a single feed or drop of the machine and by actuating the needle cylinder with an alternating rotary motion about its own axis through a rotation angle of approximately 180xc2x0, so as to make one half of the needle cylinder pass at said feed or drop. The needles of this half of the needle cylinder are made to knit at the feed or drop being considered, and their number is gradually decreased, increasing the number of needles excluded from knitting starting from the lateral ends of the set, in a first step, and gradually increased in a second step, so as to achieve the characteristic pouch-like shape for the heel and the toe.
Formation of the heel and toe of the hosiery item, due to the need to actuate the needle cylinder with an alternating rotary motion about its own axis and at a reduced speed owing to the fact that the direction of rotation of the needle cylinder must be reversed cyclically, considerably affects the overall duration of the production cycle of the hosiery item.
In order to reduce the time required to form the heel and toe of hosiery items, methods have been proposed which allow to form a pouch at the heel and at the toe by actuating the needle cylinder with a continuous rotary motion about its own axis and by interrupting, by cutting the thread, the additional rows of stitches that form the pouch. Although these methods unquestionably speed up the hosiery item production cycle, they have the drawback of producing a hosiery item that is not fully satisfactory both from an aesthetic standpoint and in terms of comfort because of the presence of the cut trailing threads on the reverse side of the hosiery item.
Other methods have also been proposed which consist in forming pouch-like knitting by again actuating the needle cylinder with an alternating rotary motion about its own axis but by using a larger number of feeds to form the pouch.
These other methods have the drawback of producing a pouch that is not fully satisfactory from an aesthetic standpoint, since holes are formed in the regions of the pouch that correspond to the reversal of the rotary motion of the needle cylinder about its own axis that increase in size as the number of feeds used increases.
Other proposed methods that use multiple feeds, aimed at reducing these shortcomings from an aesthetic standpoint, are unsuitable to provide the characteristic shape for the heel and toe of hosiery items.
The aim of the present invention is to solve the problems described above, by providing a method for forming a pouch in a tubular article, particularly for forming the heel or toe of hosiery items, with circular hosiery knitting machines having at least two feeds, which allows to obtain, in significantly shorter times than required by conventional knitting, a pouch whose degree of finishing is comparable with the degree of finish that can be obtained with conventional heel or toe knitting.
Within this aim, an object of the invention is to provide a method that allows to provide a pouch in a tubular article, particularly a heel or toe of hosiery items, that is fully satisfactory also as regards comfort.
This aim and this and other objects that will become better apparent hereinafter are achieved by a method for forming a pouch in a tubular article, particularly for forming the heel or toe of hosiery items, with circular hosiery knitting machines having at least two feeds, characterized in that it consists in using a set of contiguous needles of the needle cylinder; in actuating the needle cylinder with an alternating rotary motion about its own axis, through a rotation angle that is suitable to make the needles of said set that are made to knit pass in front of n feeds or drops of the machine which are used to form the pouch; in gradually decreasing the needles made to knit at least one of said n feeds, excluding every time needles located at the lateral ends of the set in at least one step of the knitting process; and in gradually increasing the needles made to knit at least one of said n feeds at the lateral ends of the set in at least one other step of the knitting process, each one of the two end regions of the pouch being formed by means of at least two needles that are made to knit at one of said n feeds, one of said two end regions being formed with one of said n feeds, the other of said two end regions being formed with another one of said n feeds.